Many contemporary engine controls have integral misfire detection systems. With ever-increasingly more stringent emissions standards the assurance of accurate and complete of misfire detection under all engine and vehicular operating conditions is becoming mandatory.
Commonly, system designers rely on measurement of crankshaft engine angular velocity, and sometimes crankshaft or other forms of, engine acceleration, both dependent largely on engine torque produced during a firing process to determine misfiring of a particular engine cylinder. Typically, misfires are predicted by various signature analysis, and/or spectral analysis, methods that analyze the velocity or acceleration information provided.
In a typical prior art misfire detection systems the system's main microcontroller is often charged with analyzing the misfire event. As misfire detection over all operating conditions becomes required a greater burden is shared by the main microcontroller in completing this task. This becomes particularly difficult at high engine speeds because the main microcontroller must forfeit much of its resources to service the misfire detection strategy. This requires a significant increase in the complexity of the main microcontroller.
What is needed is an improved signal processing approach for misfire detection, particularly one that is less resource intensive particularly at high engine speeds.